Fire detecting device



1941- s. T. VAN HOUTEN 2,267,541

FIRE DETECTING DEVICE Original Filed Jan. 19, 1940 I N V EN TOR. (5/30/90? 7 Van/70w? BY, a

A TTORNEYS.

Patented Dec. 23, 1941 FIRE DETECTING DEVICE Stephen T. Van Houten, Allendale, N. L, assignor to Lowe Laboratories, Inc., New York, N. Y., a corporation of New Jersey Original application January 19, 1940, Serial No. 314,622. Divided and this application July 2, 1941, Serial No. 400,760

11 Claims.

This invention relates to devices responsive to the action of heat, as the heat generated by a fire, and which shall be adapted, when actuated, to give a signal or sound an alarm or energize any other desired object and preferably employed in conjunction with any suitable fire extinguishing and control system or apparatus.

The device of the invention operates, preferably, on an abnormal rate of rise in temperature as contra-distinguished from the attainment of a predetermined fixed degree of temperature and it employs an air chamber containing a flexible diaphragm mounted therein which is flexed or distended by the expansion and consequent pressure of the air in the chamber under the influence of heat, as is well known in the art, to close an electrical circuit and energize a signal or other object.

The invention has for its principal object the production of an air chamber and associated parts of the general character heretofore referred to which shall be extremely simple in constuction and of few parts and which shall be susceptible to long life without the necessity of repair or replacement.

A further object of the invention is the production of a device of the character above described which shall be provided with a supporting plate or analogous element for normally supporting the flexible diaphragm to prevent it from sagging or collapsing and to render it resistant to abuse, rupture or other impairment.

A further object of the invention is the inclusion in the device aforesaid of means for normally retaining the diaphragm in engagement with the support, the retaining means preferably having the dual function of being a conductor for closing an electrical circuit for purposes heretofore referred to and upon the functioning of the device under an abnormal rate of rise in temperature.

Further and other objects and advantages will appear as the'description of the invention proceeds, the invention consisting in the novel heat detecting device hereinafter more particularly described and then specified in the claims.

In the accompanying drawing illustrating a practical embodiment of the invention:

Fig. 1 is a side elevation of a unit of which the device of the invention may constitute a part.

Fig. 2 is a side elevation of the supporting body or element of the unit of Fig. 1 which the detachable air chamber or fire detecting device of the invention removed.

Fig. 3 is a top plan view of the rate-of-rise of temperature chamber embodying the device of the invention.

Fig. 4 is a bottom plan view of the supporting body shown in Fig. 2, and

Fig. 5 is an enlarged section taken through the device of the invention.

Referring in detail to the several figures of the drawing:

A box-like, annular supporting body or element is indicated at Ill and is provided with perforated ears I l whereby it may be conveniently and detachably secured to a ceiling or other suitable support. Its outer or lower face I! is provided with bayonet slots l3 for reception of current conducting prongs to be hereinafter described. Metallic spring contacts (not shown) are suitably positioned within said body It] and preferably in alignment with or adjacent to the bayonet slots I3. These spring contacts may be connected, as is manifest, with a source of current supply, such as a battery, and a bell or other signal or any other object or device to be energized (also not shown) when the contacts are electrically bridged or connected together. The outer or lower face l2 of the body or element in may also be provided with an opening or depression I4 for a purpose to be hereinafter explained.

The annular flanged head of the air chamber of the device of the invention is indicated at l5 and is preferably composed of an insulating material. Secured to the head, by suitable screws l6, are the current conducting angled prongs H for reception by the bayonet slots i3 and for engagement with the electrical spring contacts in the body 10 previously referred to. Obviously, when the prongs I! are inserted in the enlarged portions of the bayonet slots l3 and the head I5 is rotated, the head is detachably locked to the body with the prongs making contact with the contacts in the body.

A contact post It}, in the form of a screw, is mounted in the base I5, preferably centrally thereof, and it is held in any desired adjustable position therein by means of the upper and lower washers l9 and the nut 20. When the head is detachably secured to the body ID in the manner previously described, the upper end of the contact post l8 and the nut 20 are received within the opening or depression I 4. A metallic connecting strip 20 connects the left-hand screw l6 and the contact post 18 and is preferably interposed at an end thereof between the base I5 and the lower washer I 8. If so desired, air relief or equalizer openings 2| may be provided in the head l5 to admit air to the interior of the device.

A thin, hollow, metallic shell, preferably semispherical in configuration, is indicated at 22. This shell may be conveniently slipped over the downwardly depending circumferential flange of the head l5 and frictionally held thereto as indicated in Fig. 5. An annular supporting plate 23 is loosely mounted in the shell 22 as shown, and is firmly supported therein beneath the flange of the base by the wall of the shell itself. Said plate 23 may be provided, if desired, with a thin metallic button 23' positioned centrally thereof although this is not a necessity. The plate also supports a thin, flexible and preferably metallic diaphragm 24 thereon which may be corrugated with a plurality of concentric corrugations as illustrated. The edge of the metallic 'diaphragm is firmly held and detachably clamped intermediate the supporting plate and the lower side of the flange of the head l5 and may also be clamped, if desired, intermediate the side of said flange and the wall of the shell 22 adjacent its peripheral free edge. This permits movement of the diaphragm centrally thereof while it is held locked at its edge to prevent displacement thereof. As is manifest, the supporting plate 23 provides a protective support for the diaphragm to obviate any likelihood of its sagging or collapsing and further rendering it resistant to abuse, rupture or other impairment.

The supporting plate 23 with the diaphragm 24 supported thereon provide with the head and the shell 22 two air chambers which have been designated as A and B, chamber A being a rate-of-rise air chamber and chamber B being a relief chamber, the supporting plate 23, obviously, constituting a wall of chamber A. Said plate 23 and the diaphragm 2d, moreover,

are both provided with a plurality of breather air vents or openings 25 whereby both chambers are normally at atmospheric air pressure. Gradual or normal changes in temperature, accordingly, will be compensated for with the air pressure in both chambers A and B equalized because of the inclusion of the air vents or breather openings 25 and the equalizer air openings 2i.

A spring metallic strip 26, or other suitably formed spring element, is also provided and is I carried by the right-hand screw l6 within chamber B and it engages and bears against the upper side of the diaphragm 24. Said spring 26 has the dual function of acting to retain said diaphragm in engagement with the supporting plate 23 and normally disengaged from the contact post l8 and of forming an electrical conductor between the contact post l8 and right- -hand angled prong I! to bridge these terminals and close the circuit when the device is operatively mounted on the body It) and operates in i response to an abnormal rate of rise in temperature.

When the head I5 is properly mounted on the body It] with the angled prongs H engaging the contacts within the body in the manner previously described, a sudden or abnormal rise in temperature brought about, for instance, by the presence of a fire, acts to expand the air in chamber A to an extent and at a rate wherein the expanded air cannot be accommodated by the breather openings 25 and relief openings 2|. In a case of this character the force of the expanded air will exert pressure against diaphragm 24 to distend said diaphragm upwardly against the action of the spring strip 26. This action, manifestly, results in electrically bridging the contact post l8 and right-hand screw I 6 as, in the embodiment shown, said spring strip is forced by the diaphragm into engagement with the lower end of the post I 8 and thereby close the electrical circuit and energize the signal or other object hereinbefore referred to. I may include in the circuit, any other energizable device, either in lieu of or in addition to the signal, which is energized by the closing of the circuit and which may perform any useful function. For instance, the closing of the circuit might be employed to open the sprinkler heads in a fire extinguishing and control system or apparatus or to open the main control valve in a system or apparatus of this character to permit the flow of the fire extinguishing medium, such as water, to the system.

Obviously, spring means of any character might be employed to normally holdthe diaphragm 24 in engagement with its supporting plate 23 and in some cases I prefer to employ a conductor other than the spring to bridge the terminals and close the circuit when the device functions. For instance, upon the expansion of the air in the chamber under the influence of an abnormal rate or rise in temperature, the diaphragm could be distended upwardly into direct engagement with the central contact post or screw and the circuit could be completed by a separate conductor connecting either the diaphragm 2 3 or shell 22 with the right-hand prong H.

In some cases, moreover, the flanged head l5, instead of being composed of an insulating material, might comprise sheet metal, in which case the left-hand prong I! and the central contact post l8 normally would be so mounted on the head as to be insulated therefrom.

This application is a division of my prior application for Fire detecting and signaling unit, filed January 19, 1940, Ser. No. 314,622.

The invention claimed is:

1. A fire detecting device comprising a head, a pair of electrical terminals thereon adapted for connection with an electric circuit including a source of current supply and a device to be energized, an air chamber removably held to said head, a supporting plate forming a wall of said chamber, a flexible diaphragm supported on said supporting plate against deflection in the direction away from the head but responsive to pressure of heated air in the chamber to flex toward the head, and a circuit closing element disposed between said plate and said head. and movable by the diaphragm when the latter is flexed to bridge the terminals and close the circuit.

2. A fire detecting device comprising a head, electrical terminals thereon adapted for connection with an electric circuit including a source of current supply and a device to be energized, a hollow metallic shell connected to said head, a supporting element forming with said shell an air chamber, a flexible diaphragm supported on said element against sagging mvement in a direction away from the head and terminals but with freedom to flex toward the head and terminals under pressure of expanded air in the chamber responsive to the influence of heat, and a circuit closing element movable by the diaphragm to bridge the terminals and close the circuit when the diaphragm is flexed.

3. A fire detecting device comprising a head, electrica1 terminals mounted thereon for connection with a circuit including a source of current supply and an energizable device, a hollow, metallic shell connected to said head, a supporting plate element mounted in said shell and forming an air chamber therewith and provided with an opening therein, a flexible diaphragm supported on said supporting element and against sagging movement in the direction away from the head and terminals but with freedom to flex toward the head and terminals under pressure of expanded air in said chamber responsive to the influence of heat, and a resilient self-resetting circuit closing element movable by the diaphragm when the latter is flexed to bridge the terminals and close the electric circuit.

4. A flre detecting device comprising a head, electrical terminals thereon adapted for electrical connection with a source of current supply and an energizable device, a shell connected to said head, a supporting element mounted in said shell and forming therewith an air chamber, a flexible diaphragm seated on said supporting element and acting to bridge the terminals and close the circuit under pressure of expanded air in the chamber responsive to the influence of heat, and means positioned in said shell between said head and diaphragm and exerting pressure against the diaphragm and normally holding it in seated position on said supporting element.

5. A fire detecting device comprising a, head, electrical terminals mounted thereon for electrical connection with a source of current supply and an energizable device, a hollow shell supported by said head, a supporting plate mounted therein and forming an air chamber with said shell, 2. flexible diaphragm seated on said plate, and a spring conductor connected to one of said terminals and movable by the diaphragm to engage the other terminal under pressure of heat expanded air in the chamber acting on the diaphragm, said spring conductor normally engaging and exerting pressure against said diaphragm to hold it seated on the plate.

6. A flre detecting device comprising a head, a pair of electrical terminals mounted thereon for electrical connection with a source of current supply and an energizable device, a hollow metallic shell connected to said head, said head and shell forming a casing, a supporting element removably mounted in said casing and forming with the shell an air chamber, a flexible diaphragm supported by said supporting element, and a spring metallic strip having one end connected to one of said terminals and the other end lying adiacent said other terminal and exerting pressure against said diaphragm to normally hold said diaphragm in engagement with said supporting element.

7. In a thermally controlled circuit closer, a casing comprising detachably connected head and shell sections, electric circuit terminals carried by the head section of the casing, a substantially flat supporting plate removably mounted in the shell section of the casing and forming therewith an air chamber, said plate having an opening therein, and a thermally responsive flexible diaphragm normally lying substantially throughout its surface area in a substantially flat state in contact with the plate and supported thereby against movement in the direction away from the circuit terminals, said diaphragm being adapted to flex under the pressure of heated air in the chamber toward the terminals to electrically connect the same.

direction away from the head but responsive to pressure of heated air in the chamber to flex toward the head, and a spring metallic conducting strip disposed in the casing between the head and diaphragm and normally arranged to engage and press the diaphragm against said element, said spring being movable by the diaphragm when the latter is flexed to electrically connect said terminals.

9. In a thermally controlled circuit closer, a casing, electric circuit terminals carried by the casing, a supporting plate in the casing forming therewith an air chamber and having an opening therein, a flexible diaphragm in the casing normally resting on the plate and supported thereby against deflection in the direction away from the terminals but responsive to pressure of heated air in the chamber to flex in the direction away from the plate and toward the terminals, said diaphragm having a reinforced central portion, and a spring mounted in the casing and normally arranged to bear on the reinforced portion of the diaphragm to hold said diaphragm pressed against the plate, said spring being adapted to yield under flexion of the diaphragm toward the terminals to electrically connect said terminals.

10. A thermally controlled circuit closer comprising a head, a shell detachably engaging the head and forming therewith a casing, electric circuit terminals on the head. a supporting plate removably supported within the casing and forming with said shell an air chamber, said plate having an opening therein, a flexible diaphragm clamped adjacent its peripheral edge between the head and plate and normally resting on and supported by the plate against deflection in the direction away from the head and toward the plate but responsive to the pressure of heated air in the chamber for flexing movement in a direction away from the plate and toward the head, and a spring carried by the head and normally arranged to bear on the diaphragm to hold it pressed against the plate, said spring being adapted to yield under flexion of the diaphragm toward the head to connect saidterminals and close the circuit.

11. In a thermally controlled circuit closer, a head, a shell detachably connected with the head and forming therewith a casing, electric circuit terminals carried by the head, a supporting plate removably supported within said shell and forming therewith an air chamber, said plate having an opening therein, a thin flexible diaphragm clamped adjacent its peripheral edge between the head and plate and normally seated substantially throughout its surface area on and supported by the plate against deflection in a direc tion away from the head, said diaphragm being adapted to flex toward the head under pressure of heated air in the chamber and having a reinforced portion, and a conducting spring connected at one end with one of said terminals and having its free end normally arranged to bear on the reinforced portion of the diaphragm to hold the diaphragm pressed against the plate, said end of the spring being movable with the diaphragm when the latter is flexed toward the head tor badge the terminals and close the electric c c STEFHEN T. VAN HOUTEN. 

